chapter 25 plant responses and adaptations.. set up foldable fold long and skinny (hotdog) fold...
TRANSCRIPT
Chapter 25 Plant Responses and Adaptations.
Set Up Foldable
• Fold Long and Skinny (hotdog)
• Fold short and fat 2 times (hamburger)
• Open so looks like below, crease is on top
What is a tropism?
Tropism ~ a response of a plant to an environmental
stimulus.
Tropism
• Tropism is growth in response to an external stimulus (factor that elicits a response).
• Positive tropism: Plant growth toward a stimulus (water, sunlight)
• Negative tropism: Plant growth away from a stimulus (spilled gas, toxins, too much sun or not enough)
What is phototropism?
Phototropism ~ a tendency of plants to grow toward a
source of light.
Phototropism• Phototropism is a
change in the growth of a plant in response to light.
• The stalk displays positive phototropism growing towards the light.
What is gravitropism?
Gravitropism ~ a tendency of a plant to grow in a direction
in response to the force of gravity.
What is thigmotropism?
Thigmotropism ~ the response of plants to touch.
Geotropism (Gravitropism)• Geotropism is a change
in the growth of a plant in response to gravity.
• The stalk displays a negative geotropism growing away from gravity.
• The roots display a positive geotropism growing towards gravity.
Hydrotropism • Hydrotropism is a
change in the growth of a plant in response to water.
• The roots display a positive hydrotropism growing towards water.
Turgor Pressure
• http://www.kscience.co.uk/animations/turgor.htm• Click on link above for example
The cell’s vacuole does not have any water in it.
The cell is flaccid.The vacuole does not have a lot of water in it.
The vacuole and cell wall push against each other.The vacuole is now full of water.